Unable to stick on first layter

[scoutty 1]

So I have had my Ender 3V2 for about two months, printed a lot of stuff without any problems. Now it seems I can hardly print anything now without issues on the first layer. Wonder if anybody can give me a clue what is happening. I level it by paper method, then went to the BLTouch and had nothing but problems. Nozzle would slam into glass bed, nozzle would scar the surface of the bed. So I decided to take it off and start fresh. But seems I can't get the bed level anymore., I do have the update springs and new glass bed. Doing the 4 square test print and the skirt is perfect, sticks pretty good, then the bottom left square prints good, then the top left square prints and doesn't even stick to the bed. I think my bed is unlevel but not enough to warrant a warranty replacement, according to creality. Each time I level with the paper method I get it perfect, next print I have to level the bed again as it is way out. I've also done the slow down to 20mms. No help

 

Here's an example,

 

https://www.snippetlibrary.com/3d/HalfTestPrint.mp4

https://www.snippetlibrary.com/3d/FirstLayer.mp4

 

The white I am using is a Eco White, could it be that leaving a film inside the nozzle and making any color after a mess? example images:

 

 

[gr5 2,172]

Your leveling looks good (but hard to tell without being there in person).  One quick thing to verify it's not the leveling - push up and down a little with your finger on the bed to see if pushing it up (or down) makes it better.  But it looks fine to me.

 

I'm thinking you got some oil on the bed.  Maybe oils from your fingers.  Or maybe you oiled the rods and a drop fell to the bed without you noticing.

 

I'd clean the bed well with soap and water.  I don't know anything about Creality beds so for all I know soap will destroy the bed so look up how to clean.  But in general soaps and detergents are needed to remove oils.

[scoutty 1]

Thank you sir, I do use isopropyl alcohol to clean the bed. So on the picture with the white, why does it bump up like that?

[scoutty 1]

The links seem broke, so copy the text and it will work, the url is wrong but what it shows it correct

[gr5 2,172]

@GregValiant - you've got an Ender, right?  What do you think?  Is the bed faulty or is the nozzle too far from the bed?

 

[GregValiant 1,250]

Hi gr5.  Looking at the picture of the white model the skirt looks pretty good and so do the loops of the model itself.  They look like they welded together so the height couldn't be too far off.  On the other hand, the first layer skin is a mess.  Scouty, gr5 made an in-depth video on bed adhesion that covers most issues.  For me, I clean the glass with IPA, and then give it a dusting with Aquanet Super Hold hairspray, and I level with a piece of parchment paper.  I get consistently good starts to prints.  Since gr5's video will cover adhesion, I'll go over some things about leveling (setting the gap) that you might be running into.

 

These are a few mechanical things that can mess up leveling and make it so inconsistent it drives you nuts.

• The wheels on the Y trolley can loosen up / wear in.  That causes wobble and leveling is very inconsistent and can change by a lot from one print to the next.  You can adjust the eccentrics on the wheels on the Y trolley and take any wobble out.  Like the other wheels, you should just be able to turn them by hand.  you might also want to make sure that the beam that the trolley runs on is square to the rest of the frame.  Mine was off by 3° and it was near impossible to level.  The screws that mount it are the 4 below the Z uprights on both the right and left sides of the machine. 
• The stop switches on these printers aren't high quality and so the repeatability of the stop position varies.  The stop position can vary by .25mm over to .25mm under.  That isn't so important in the X and Y but for the Z it's what sets the "0" for everything.  Example:  You're going to start a print and you Auto-Home and that gives a Z=0, then you level the bed however you want (BLT or paper) and then the print starts and there is a G28 so the printer Auto-Homes again and this time the Z is .25mm above (or below) where it was during your leveling.  Now the first layer height is totally wrong and you either scrape or the plastic doesn't want to stick.  You might be able to swap the Z switch with the X or Y switches.  One of them might be more accurate (if this is the problem).
• If the right end of the X beam has movement up and down (wiggle it), and when you are leveling, you move the Z up, then go to the next leveling position, and then move the Z down, on the right side the movement is different than on the left side.  That causes inconsistent leveling.

You know that the first layer has to go down right.  Get your tools out and go over the mechanicals of each axis and remove any slop that might be there.  After that, if it is still inconsistent, take a good hard look at what is going on with the Z stop switch and check the set screws on the Z coupler as well.  Take a break by sitting down with a bag of popcorn and watch gr5's video.  He covers a lot of material in it.

 

Now about those zits...I don't think I've ever seen that before.  I print regular PLA at 210 but white at 195-200.  There is just so much colorant in it (titanium oxide?) that it's tough to get right.

 

The Gcode file I've attached is a leveling routine.  The print head will home and then move to a corner and wait.  When you're ready for the next position click the button on the LCD.  Some Ender 3's with the 4.2.X boards don't pause correctly but for most the M0 pause command does work.  The bed and hot end temperature lines are commented out.  If you remove the semi-colons from in front of the lines then the bed and hot end will heat up.

Level.gcode

[scoutty 1]

@GregValiant, I total get what you are talking about. I have sat down, tore everything apart and started fresh to make sure everything is tight. I can't wobble the bed and the z axis is tight and level. I will look at those videos, anything helps. The last two points you made seems exactly what is going on. I turn it on, auto-home, level the bed like 4 times. Print, same result. Turn it off and do it all over again, and the bed will be like way off. As I'm leveling and I just put my hand on the wheel screws I can feel the paper loosen, take my fingers off and the paper is tight again, without turning the knob. With those upgraded springs how can it be so touchy?

 

I also took the nozzle off and made sure it was clean because the white that I used wasn't coming out correctly as the black does. Black strings out, the white balls up right at the nozzle. So when I took it all apart I noticed a "goo" in the nozzle and heater, is that normal and could it be from the PTFE (Capricorn) tube? goo is hard to explain, more like a oily residue. So I cleaned the nozzle, put a new tube in and printed, didn't change anything. The white is a Enomaker brand ST-PLA, first couple of prints on that turned out good, then I started having issues, was thinking it was leaving behind a residue.

 

Those zits cause issues sometimes. If one is sticking up and the nozzle catches it, it rips up the plastic from the bed. Kind of like dragging it.

 

Thanks for the level code, I'll try it when I get time. And check the beam for the trolley, I didn't check that part either.

[GregValiant 1,250]

The black goo is the PLA breaking down from the heat and it causes high friction at the end of the bowden tube.  You can cut 3 -5mm off the end of the bowden and re-install the bowden.  That is normal maintenance and it's why the bowden tubes are consumable parts of the machine.  With the nozzle out, shove the bowden tube down through the hot end and push out any plug of plastic that might be in there.  I do full machine maintenance once per month whether it needs it or not.

The Y bed travels fore and aft on a 40 x 40 beam (the yellow beam in the image).  That beam is connected to the bottom 40 x 40 cross beam (green in the image).  There are 4 screws on the left and 4 screws on the right that are directly below the 40 x 20 vertical Z beams that hold the green beam in place.  So if the green beam isn't exactly square to the machine, the gold beam is at an angle and so the Y bed is at an angle.  Many Ender's are assembled like that causing the Y beds (the trolley) to run up and down hill.  Leveling isn't inconsistent, just wrong.

 

These are at the same time one of the simplest and the most complicated machines I've worked on.  Everything affects everything and so each machine part must be adjusted correctly to take it out of the problem equation.  As you've learned, troubleshooting is a big part of owning a Creality printer.  The "Tune" is on a knife edge and once it falls out of tune it can be damn hard to chase the problem down.  That's why I'm so fussy about maintenance.  When there are several problems at once, and they are over-lapping, and any of them could cause the problem we are having, then frustration creeps in.  One thing at a time is the way to approach it.  I was over-thinking a problem I was having with the Z location and finally looked closely at the Z switch.  There was some strings of PLA that had gotten caught in it.  It was one of those "DUUHH" moments.  Highly annoying.

 

[gr5 2,172]

Ultimaker did a test around 10 years ago on those limit switches and found them consistent to better than 0.01mm (one hundredth!).  My memory of the accuracy could be wrong but I remember they were really surprised at how consistent they were. These were cheap limit switches from China most likely.  Also the Z height in an Ultimaker printer after leveling stays consistent for over a month.  I only have to relevel if I change a nozzle.  I'm not bragging - just saying it's probably not the switch exactly but some other mechanical thing that is inconsistent.  Or maybe Ultimaker was just lucky with their limit switches and Ender unlucky.  But I suspect it's not the switch itself but something around the switch.

[scoutty 1]

Thanks guys, I was hoping it wasn't a limit switch, lol. I have been doing some more research and it tuns out that the "zits" are a common thing and can be caused by the extruder spitting out more filament than needed because of the pressure in the nozzle. This can be fixed by settings in Cura called the Mesh Fixes. Specifically the Max Resolution, Max Travel Resolution and Max Deviation. Setting them down to 0.05 has so far curbed my zit problem, still a little there but nothing like before. It usually can happen on a new layer or on each transition between lines or walls as the speed changes, common reason for zits / blobs.

 

Common issues:

• If the defect appears right away at the beginning of the loop, then it’s possible your retraction settings need to be adjusted slightly.
• If you notice a surface defect right at the beginning of the perimeter, then your extruder is likely priming too much plastic.

Hope this helps somebody as there is a lot of good info in this thread. Appreciate all the feedback guys.

[GregValiant 1,250]

@gr5 10 years ago they were probably "high quality" Taiwanese switches.

 

When I have to restart a print and I'm forced to include a G28 there is almost always a layer shift of up to .5mm.  It's the switches on the Ender.  My Z switch is actually pretty good but the X switch in particular is terrible.  The 1 out of 3 gives me an Acceptability Rating of 33%.  I think the most I get out of a "leveling" session is about 5 prints.  Part of that is removing the glass to get the print off, but 30 days on this thing?  Ain't no way.

[gr5 2,172]

I don't know what to say.  It's not like Ultimaker spends a ton of money on parts.  I seem to remember their Z nut in the UM2 was like $1 and someone said the $3 Z nuts were 10X better and Ultimaker should not be so cheap.  But an Ender is a whole 'nother level of cheap I suppose and may use 1 cent limit switches instead of 5 cent limit switches (numbers grabbed from thin air).

 

And 30 days is the low end.  I've just never gone longer without changing nozzles.

[scoutty 1]

Well as I said things were good, it hit the the second and third layer of my print and I can see it now more then ever on over extruding. So at least I now what is happening now and have things to look at. I can literately watch the filament come out at the end of the line, creating the zit or blob.

 

I have read that some guys get 6 months out of a level after upgrading springs and adding a BLTouch. I got a month max on the first level. lol

 

[gr5 2,172]

I could be wrong but isn't BLTOUCH an automated bed leveler?  I'm talking about the UM2 which has no autlevel capability - just manual level.  Once you get the manual level dialed in it stays.  No need to level again.  Probably ever.  But I change nozzles a lot so I have to relevel a lot.  I sell a set of nozzles that are the same length to 0.01mm but I'm too cheap to use it myself.  I don't mind leveling.  I do it on the fly while it prints the skirt.

[GregValiant 1,250]

"But an Ender is a whole 'nother level of cheap..."

 

Amen brother.  Every body who owns one ends up replacing the fans at one point or another as the sleeve bearings wear out or the fans just quit.  This is not to mention how noisy they are.  And the layer cooling blower is a proprietary design so the only direct replacement for a stock piece of crap is another stock piece of crap.  It's one of the main reasons that so many owners move to a 5015.  (I don't get a lot of the fan contraptions I see on Enders though.  They are borderline ridiculous.)

And it is my (never humble) opinion that the switches are every bit as good of quality as the fans.

[GregValiant 1,250]

2 hours ago, scoutty said:

I have read that some guys get 6 months out of a level after upgrading springs and adding a BLTouch. I got a month max on the first level. lol

Those are the same people who regularly print at 1000mm/sec.

 

Are your E-steps calibrated?  That would be the first thing to check.

You can tune the "Flow" on the fly.  You might try that to work towards an acceptable finish.

 

I've attached a little ditty I wrote.  It's a Windows app (I don't know what OpSys you are using) that I call "Greg's Accel and Jerk Tool".  If nothing else it's an interesting toy.  Start out slow as high speeds with high Accel and Jerk numbers can cause missed steps or even belt skipping (we are talking about Creality printers after all).  It's an unsigned app and if you decide to try and install it you might have to convince your anti-virus to let it install.  It requires a USB data connection to the printer.

 

 

Greg's Accel and Jerk Tool.zip

Edited March 27, 2021 by GregValiant

[scoutty 1]

Ok guys, I got a new extruder. I have calibrated my eSteps as well.  I think that solves the biggest problem. So, here is the latest print job. I see what is happening here. Where it is now, I can see it lay the line perfect, but when it comes back the other direction it actually messes up the line it just did. So its not over extruding anymore, its just messing up lines it just laid down.

 

See the corner, perfect bed leveling. Seems to be only the middle where the lines bulge. Ideas?

[GregValiant 1,250]

Is that a new nozzle as well?  I've had some bad ones that had burrs on the end.

You replaced the hot end...is it straight up and down?  If the nozzle isn't exactly square to the plate then one direction will extrude differently than going in the other direction.  Cotton candy fuzz is evidence of that.

Another thing to check would be to make sure you aren't getting any leakage out of the top of the heat block where the heat break screws in.  Usually the blobs are a lot bigger but a quick look can tell if it's a problem.

[scoutty 1]

That would explain it then. I didn't replace the nozzle but I did have it off cleaning it up. I bet its not straight. Thanks Greg I will look into that. What is the best way to get it perfect? I did have a heck of a time trying to tighten it back up and get what I thought was straight.

[GregValiant 1,250]

I guess you can just eyeball it.  I use a carpenter's tri-square sitting on the bed.  The hot end needs to be square when looking from the front and when looking from the side.

[scoutty 1]

Thanks for the help guys, it was the nozzle off just a little bit to the right. Makes sense now. I appreciate the help and insight.